House Minority Leader Nancy Pelosi said Tuesday that congressional Democrats were united in support of President Obama's decision to order air strikes in Iraq as "humanitarian assistance" for refugees trapped by Islamic militant fighters, but added that "we don't consider boots on the ground an option."

Pelosi, D-San Francisco, said 100 House Democrats held a conference call Monday after Obama notified Congress that 275 U.S. troops were being deployed to Iraq as security for American diplomatic personnel in Baghdad. His notification, made under the War Powers Act, came two days after U.S. warplanes fired on Islamic State militants who have bottled up refugees near the Syrian border.

Pelosi said that "across the board, the full spectrum of our members support the president's call for humanitarian assistance (and) recognize the need to protect Americans who are there by stopping" Islamic State forces.

U.S. troops left Iraq in 2011 after an eight-year war. Although House Democrats have made it "very clear" that sending combat forces back to the country is unacceptable, Pelosi said, she left open the possibility that U.S. actions in Iraq could reach "a place where we need congressional action."

Pelosi made her remarks after a press conference in San Francisco where she was asked about misgivings among liberal Democrats such as Rep. Barbara Lee of Oakland, who cautioned against U.S. "mission creep" in Iraq. Lee also urged Obama last week to "seek congressional authorization for any further combat operations."

Pelosi said Tuesday that Lee's concerns were not confined to the left - "that's the general view in our caucus."

"Certainly, (Obama) has consultation with Congress ... and that was very intense this past week," Pelosi said.

"In the meantime the president, through the War Powers Act, has a great deal of power," Pelosi said. "He has to inform us and he has 60 days" to deploy troops to Iraq without receiving congressional approval, "and we'll see how many times he does that."

Pelosi took a swipe at Republicans who have criticized the U.S. air strikes as a half-hearted response to the belligerent Islamic militants, saying, "This Iraq war was a mistake from the start. We were led into it on the basis of a false premise. ... So for all these people that took us down this path to be criticizing the president's actions now is ... not surprising, but nonetheless, it's not credible."